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From: peterson@fman.enet.dec.com (Bob Peterson)
Newsgroups: comp.sys.hp,comp.sys.dec,comp.lang.fortran
Subject: Re: f77 comp option to swap bytes?
Keywords: f77 compiler byte swap hp dec ultrix fortran
Message-ID: <1991Mar22.132140@fman.enet.dec.com>
Date: 22 Mar 91 18:21:40 GMT
References: <traymund.669594979@uiwpl.ece.uiuc.edu>
Sender: news@shlump.nac.dec.com
Reply-To: peterson@fman.enet.dec.com (Bob Peterson)
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Organization: Digital Equipment Corporation
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In article <traymund.669594979@uiwpl.ece.uiuc.edu>, traymund@uiuc.edu 
(Tim Raymund) writes:
>Is there a f77 compiler option to swap byte order on i/o?  I ran
>the same program on a DECstation 5000 and an HP 9000/835 (see program
>at the end) and the resulting files look like:
...
>We like to use binary file i/o as in the program, and it would
>be handy if a f77 compiler option could be set to make the
>files identical across systems.

Yes.  The DEC Fortran V3.0 compiler might help.  It is capable of byte
swapping and VAX<->IEEE conversion on binary I/O.  The drawbacks of
this are that FORTRAN programmers sometimes equivalance a lot of data
in COMMON to a single integer vector, and then do I/O with the vector.
The conversions then may fail.

The experimental support allows you three options to control this: a
per-unit environment variable, a compiler option affecting all units,
and a new OPEN statement keyword, CONVERT.  Details on request.  We
haven't had enough experience with this to catch all the gotchas.  One
gotcha: the binary data may be converted, but the binary record formats
have to be the same as well.  We think we match formats pretty well,
but like I said, we're in learn mode.

\bob